Andy Warhol was not a regular at the San Remo although many of the regulars there would later become part of the Factory. Warhol preferred to hang out at the Serendipity Cafe uptown.

Andy Warhol (via Pat Hackett in Popism):

All the amphetamine men - A-men
- fags on speed who would howl laughing at the very thought of going to
a gay bar, loved the San Remo... A lot of the San Remo boys
used to write for a mimeographed sheet called The Sinking Bear (named after a poetry magazine that was around then called The Floating
Bear), which was one of the first underground newsletter/papers.
(POP55)

Ondine, who was one of the writers, would sit in his booth
at the San Remo armed with Magic Markers writing replies to people with sex
queries/problems for his column. (POP55)

Another regular at the San Remo, who also hung around the factory
in the early days, was Rotten Rita.

Andy Warhol (via Pat Hackett in Popism):

[Rotten Rita] was still employed, at
some factory that made fabrics - velvets or something - and hed come
by with yards of this and swatches of that. This was before he started stealing
cars but probably during his bad check period. In those days, he and Binghamton
Birdie always went around together. Rotten was about six feet tall, and
he had kind of a collegiate look like a goofy computer repairman - very
sharp, chiseled comic-book features. And Birdie was a good-looking type
with big muscles; he looked like something out of a physique magazine."
(POP76)

Mary Woronov said that Rita was known to have the worst
speed in New York. Rita would later claim that he was killing his father
by spiking his coffee with megadoses of speed that often left the old
man mumbling ninety miles an hour to a light bulb. (MW102)

Rotten Rita's friend, Binghamton Birdie, was responsible for the pornographic graffiti mural in the bathroom of the Factory. Warhol filmed two Screen Tests of Birdie in 1964. Birdie also appeared in Couch. His real name was Richard Stringer. (AD38) Warhol did not film a Screen Test of Rotten Rita.